Scleral lenses are a special type of rigid contact lenses used to vault over the cornea, leaving a space between the contact lens and the cornea. Scleral lenses are often used for patients with corneal problems such as keratoconnus, irregular astigmatism, surgically induced corneal irregularities, or persistent corneal defects. These patients often already have diseased or compromised corneas and therefore wearing of contact lenses need to minimize the potential for additional damage and patient discomfort. To provide acceptable vision, a solution is often used to provide a liquid interface that fills the void between the lens and the cornea.